Setts



APPLICATION FILED DEC- l9. I918.

Patented July 22, 1919.

2 SHEETS-SHEET I.

A. W. CARLSON I METHOD AND MEANS FOR MAKING TURBINE ROTORS.

APPLICATION FILED DEC. I9. 1918.

2 SHEETS-SHEET 2.

1,3 1 1,109. Patented July 22, 1919.

UNITED STATES PATENT OFFICE.

AXEL W. GARLSON, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO CARLING TURBINE BLOWER 00., OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS.

METHOD AND MEANS FOR MAKING TURBINE -ROTORS.

Specification of Letters Patent.

Patented July 22, 1919.

Application filed December 19, 1918. Serial No. 267,540.

To all whom it may concern Be it known that I, AXEL IV. CARLSON, a citizen of the United States, residing at lVorcester, in the county of lVorcester and State of Massachusetts, have invented certain new and useful Improvements in Meth' ods and Means for Making Turbine-Rotors, of which the following is a specification.

My present invention relates to certain features of novelty in the method of producing turbine rotors having a plurality of impact stages or completely assembled rings of blades, vanes or buckets; also to means peculiarly adapted to facilitate the carrying out of the method for the manufacture of such rotors; the objects being to render the production or making of turbine rotors of the characters specified; more convenient, simple and economical in manufacture; and to produce better, more accurate and efficient rotors for use in elastic fluid turbine engines.

Another object is to attain a method whereby the series of blades are primarily assembled and secured in their regular order and relation, together with outer and inner concentric circular bands; thereby forming a complete practically non-distortable blading annulus, that can be handled, transported and treated in more or less careless or rough manner without causing in]urious derangement therein, but maintaining its prepared condition ready at any time for use as a conveniently placeable unit, in subsequent steps of the manufacture.

Minor objects and features of invention will appear set forth in the following detailed description, and as illustrated in the accompanying drawings, wherein Figure 1 represents a plan view of improved means adapted for employment in the method of making turbine rotors in accordance with my invention; portions being shown broken away the better to reveal the structure. Fig. 2 is a cross section of the same at line X X on Fig. 1. Fig. 3 represents (on smaller scale) a plan view of a finished rotor having .two stages or sets of blades or vanes; por

tions beingbroken away to reveal the under set of blades. Fig. 4 represents across section through the side of the core-box, clampplates and intermediate separator element; showing said parts as relatively positioned, but slightly away from each other. Fig. 5 represents a separate planview of the intermediate separator annulus, with d0t-anddash lines indicating the manner of releasing the sections from between the dual rows of blade shanks. Fig. 6 is a cross-section of the separator annulus taken on line Y Y on Fig. 5. Fig. 7 is a separate view of the blading annulus, or series of blades and circular bands, as assembled and secured in their complete order and relation preparatory to their incorporation with core-forming means. Fig. 8 is a detached View of one of the blades, and one with cross-sections of the inclosing bands with which the blades are assembled and secured, and Fig. 9 is a cross section view through one side of the turbine engine, showing the relation of the plural staged blading to the engine casing and intervening stationary sector of re versed blades.

In the manufacture of turbine rotors of the character referred to, the blades or vanes 5 are individually formed with a reduced longitudinally extended shank 6 at the in ner end, and a short projecting stud or tenon 7 at the outer end; the body of the blade being of the usual concavo-convex cross-sec tion form. The effective working length of the balde is made to correspond with the desired radial dimension of the particular stage or circular row of blading in which it is to be used, since the respective stages may be of different widths.

In practice, as employed in turbine engines, the parts may be relatively disposed substantially as indicated in Fig. 9, wherein C denotes engine casing; c the steam injecting nozzle or passage; 4 the rim of the rotor; a the first stage or row of blades; 1) the second stage or row of blades; the blades of both stages being rigidly fixed, by casting, 1n the rotor mm.

D indicates the stationary sector of reversely positioned blades (Z disposed inwardly between the two stages a and b, and supported in the sector body D that is firmly secured within the engine casing C.

The sector-blades (Z serve to direct the flow of steam or elastic fluid, after passing the first stage, to impinge in proper direction against the blades of the second stage.

-According to my improved method I primarily provide two complete circular bands 2 and 3 of comparatively thin fiat metal, preferably rolled bronze or harddrawn brass, and dimensioned for concentric disposal with intervening area equal to the length of the blades 5. Each of said bands is perforated with a series of holes therethrough, numerically corresponding tothe series of blades, and shaped to approximately fit their projecting ends; the open-. ings in the inner band to receive the shanks 6, and those of the outer band to fit the tenons 7.

As a permanent ring or annulus, the full series of blades 5 and bands 2 and 3 are pre paratively assembled with the shank (3 of the blades extending through and project-- ing inward within the inner band 3, as at 20, and with the outer end tenons 7 passed through and secured in the openings of the outer band2, preferably by riveting down their outer ends; which can be readily effected by the aid of a suitable form or jig for temporarily supporting the members while being arranged and secured together. By this method of primary assembling the series of blades, with an outer and inner circular band, both ends of the blades are confined against displacement and there is produced a complete dual rimmed annulus of blading, which is comparatively firm laterally and in circle, and can be handled, transported and treated without extreme care in the works, since the particular structure of this prepared bladingannulus is peculiarly adapted to resist disarrangement or distortion of its parts, and for maintaining, for any length of time, its primal condition as .a conveniently placeable unit of the character shown in Fig. 7.

For preparing the thus assembled series of blading for having the body-wheel cast in connection therewith, the main portion of theblades and outer band.areembedded in a. protecting annulus of core material formed thereon, substantially as hereinafter explained. For this purpose I provide a circular core-box 10 having a circular shoulder 11, and adapted for supporting the annular bottom clamp-plate 12 concentric therewith; said clamp-plate being peripherally of a size that fits the inside circle of the inner band 3. A substantially similar upper clamp-plate 13 is also arranged in the box 10. Said clamp-plates are provided with spaces 5 and 5" for the reception of the shanks 6 of the blades.

A separator element 15 is arranged intermediate the clamp-plates 12 and 13. Said separator element consists of a flat annulus composed of segments or sections separably joined, so that its sections can be retracted or moved backward within the area of its circle. As illustrated in Fig. 5, it consists of four segments, two of whichn n are at their lower ends abuttingly joined or matched to the fourth, 0, by joints 7 that permit a swinging or rolling action, while their other ends are formed-with oppositely facing approximately straight surfaces :9, which may be parallel or slightly inclined,

and between which the first segment m, which is formed-with approximately straight end-faces 8' is arranged to match, so as to brace the segments a n apart for keeping the separator extended, or to be drawn back, as indicated by dotted lines m and removed; after which the second segments 02 n can be swung inward as indicated at 11. then the fourth segment 0 can be drawn back. Each of the segmental sections is provided with a loop 79 or equivalent means for its convenient retraction.

The joint faces of the segments are best madewith a narrow dressed contact surface at the periphery of the annulus, and relieved from contact at a short distance back therefrom; thus affording a perfect rigidity of the circle, but permitting ready release of the sections .without disturbing the surrounding core.

The peripheral edge of the separator element may be perpendicular to its plane, or inclined to conform to any offset between the edges of the clamp-plates below and above it.

Suitable bolts 16 are arranged through theparts 13 and 15 :and screw threaded into the bottom plate 12 for clamping them firmly upon the shanks 6 of the blades.

The clamp-plates are made of such circumferential dimension as will approximately fit within the inner bands of the assembl ed bladingannulus.

After the series of blades 5 is assembled and secured with the bands 2 and 3, as a unit, the annulus is placed upon the lower clamp-plate 12 with the inwardly projecting shanks 6 resting in the space or spaces 5" and the innerband 3 embracing the periphery of said plate. The separator ring 15 is placed upon the shanks, in annular form,- with its peripheral edge approximately alined with the inner band, then another or second stage annulus of assembled blades and bands, as a unit, is placed upon the-top of the separator element with its inwardly projecting shanks 6 resting thereon, as at 20, Fig. 1. After which the upper clamp-plate 13 is arranged in inverted relation upon this second row of shanks. and the several plates 13,15 and 12 are forced together by the bolts 16. thus firmly clamp ing the plural sets of shanks 6 in position and retaining the several dual-banded series of assembled blades in their proper stage relation. I

hen thus clamped and supported the blading annulus and clamp devices are ar ranged within the circular core-box 10; then the space 19 surrounding the clamp-plates and bands, is packed full with core material 1'7, closely embedding the blades 5 and outer band 2, and filling in against the separator 15 and exterior surface of the inner bands 3, thereby forming a complete annular core 17 containing the plurality of sets of blades securely held in place therein in their proper determined relation. This core is then baked, or treated for hardening in usual manner for cores. The clamping device, together with the annular core containing the inclosed blading and bands, is subsequently taken from the core-box. 10, the bolts 16 released, and the upper and lower clamp-plates removed.

The intermediate separator 15 can be released and taken from between the two rows of inwardly projecting shanks, by first drawing the segment 0r section m backward within the circle between the opposite joint surfaces S, as indicated at m on F iig. 5; then swinging inward the two side sections a n, as indicated by dot-and-dash lines M, and then drawing inward the remaining section 0. Thus the several parts of the separator can be readily taken from the interior of the circle of shanks, in a plurality staged blade assemblage, leaving the inclosing core intact with the shanks projecting-inward therefrom, asat 20, and faced with the inner bands 3.

This annular core containing the plurality of rings of band-connected blades, is then placed in a suitably shaped wheelmold, formed in molding sand, and the bodywheel 14 cast therein of molten metal; (preferably phosphor-bronze) the metal in the rim portion 41 of the wheeluniting with the inner bands 3, and solidly embedding the plural rows of blade-shanks 5, which project inward through said bands, thus making an integral structure. The rotor-casting is then removed from the mold and the core material freed from the blading, which is left with clear inter-spacings without requiring diflicult cleaning out between the blades.

The sides of the rotor and edges of its rim 4: are finally dressed or turned off to the size and surface finish required for use in the turbine engine.

In the present illustration the rotor is shown as made with two stages or circular rows of blades assembled between innerand outer bands 2 and 3 as described; but it will be understood that the plurality construction may include a greater number of rows of blades incorporated with a single rim or casting, in the same manner and by substantially the same method and means herein described.

In practice the plural staged rotor, as employed in the turbine engine, is associated with a sector D of stationary inverted blades d, and it may be noted that by my method and means a rotor can be readily and economically made which will run with true accuracy therewith and givehigh efiiciency of service. 7

The stationary reversing sectors D may be made by substantially the same method above described; that is, by primarily assembling and securing the series of blades in their determined order with circular outer and inner bands; inclosing the blades in an annular core and casting the body thereon; except that the shanks of the blades (Z are projected outward through the outer band instead of inward through the inner band; and the casting of the body or rim D is made upon the exterior instead of the interior of the circular annulus, the latter being cut into sectors after the casting is completed.

By primarily assembling and securing the series of blades with the outer and inner bands, as a unitary annulus, much labor and annoyance is obviated in the subsequent handling and placement of the same for casting, insuring greater accuracy in the casting operations; and clean unobstructed passages between the blades are attained.

The bands 3 being of quite thin metal and backed by core material, instead of a metal support, the liability of, chilling the molten metal when casting the body is obviated, and a more perfect integration of the wheel-rim and blading annulus results.

What I claim is 1. The method of making molds for turbine rotors, which consists in primarily forming a blading annulus by assembling the series of blades between circular concentnically disposed outer and inner perforated bands, the shank of the blades extending througli' and projecting at the interior of the inner bandsecuring the outer ends of the blades in the outer band, sup porting said blading annulus in a circular clamping device, placing the same within a surrounding core-box and inclosing the blades and outer band with core material, baking said core material thereon, then removing the clamping device leaving the face of the band and projecting shank exposed, placing the circular core and inclosed blade annulus in a suitably formed wheel-mold, and casting the body of the rotor... therein, integrant with the inner band and solidly embedding the inwardly projecting shanks of the blades.

2. The improvement in the method of making rotors for elastic fluid turbines, which consists in primarily forming a complete blading annulus, by assembling the series of blades in their regular order with an outer and inner concentrically disposed perforated band of thin flat-rolled metal, their outer ends secured in the outer band and their extended shanks passed through the inner band and projecting within the circle thereof, substantially as set forth.

v 3. In a method of making turbine rotors; preparatively assembling the complete series of blades, having outward and inward shoul- &

ders and longitudinally projecting reduced ends, with a plurality of perforated concentric blade connecting ibands by which both ends of said blades are supper-ted in their determined relative order, end'wise embraced between the bands, said assembled bands and blade-s constituting a dual-rimmed transportable unitary annulus, with the shanks of the blades projecting therefrom.

t. In the method in makin rotors for elastic-fluid turbine motors, the improvement which consists in primarily forming a preparatory blading annulus, by assembling a full series of blades in their regular order with serially perforated outer and inner circular bands of thin fiat-rolled metal, with their inner reduced shanks extending through and projecting within the circle of the inner band, their outer ends extending through and externally riveted upon the outer band.

5. In the manufacturing of turbine rotors, the method of uniting the series of blades in a blading-annulus, which consists in assembling blades having extended shanks and short tenons at their respective ends in radially disposed order between an outer and inner circular band of thin flat metal having corresponding perforations therein, projecting the shanks through one of said bands and permanently securing the tenons in the perforations of the other band by riveting down the ends of the tenons, said parts being combined as a dual-banded non-distortable annulus, for the purpose set forth.

6. The method, in making plural-staged rotors for turbine engines; which consists in assembling and confining, in the form of an annulus, series of radially disposed blades arranged in determined order between outer and inner perforated circular bands, with their shanks projecting through said inner band, supporting a plurality of such assembled blade series by their shanks, between upper and lower clamp-plates vand an intermediate separator annulus composed of inwardly withdrawable segments, forming an incasing core about the plural series of blades, then releasing the clamp-plates and drawing the segments of the intermediate separator-annulus inward within the circle, substantially as set forth.

7. The method of making molds for turbine rotors, which consists in preparatively arranging the series of blades in their proper relative order, with an outer perforated band and an inner perforated band as a unita ry annulus or ring, by projecting their shanks through the openings in the inner band and fixedly securing their opposite end tenons in the openings in the outer band, su-

perposing a plurality of such circular arranged bladerings with. their inwardly projccting shanks held between peripherally circular clamp-plates; and segmentally sectioned intermediate vseparator zannululs, then forming a unitary annular core upon and inoilosing said plurality of bladi-ng rings, detaching the clamp-plates therefrom and releasing the separator by successively withdrawing its individual sections inward witli inilt-he circle.

8. The-: method of niakingzplural staged turbinerotors; means for supporting a plurality of rings of completelyassembled turbine blades, comprising upper and lower nular clamp-plates and an intermediate annulus disposed betweensaid clamp-plates, composed of segmentalsections adapted to be individually released from the eircumferential circle thereof, and bolts arranged through said clamp-.platesiand SQPZLIZUbOIfl'H- nulus and adapted for retai-ningthe segments in ,position and lfor clamping said plates together.

9. An apparatus for :m'ald-ng turbine rotors, comprising upperand lowerwa-nnular clzmnp plates havingspaces for receiving the shanks of anvrannularly arranged series of turbine bladesand concentric bandssecuring said blades in upper and lower annular assembled stages,-.ia-n intermediate separator annulus composed of separable segmental sections individually retractable within its circle, one of said-sections adapted for re taining the others in annular position and for releasing the same when withdrawn, means forw-ithdra-Wing the segmental sections, a core-box affording an annular coreforming spate about the periphery of said clamp;plates and separator annulus, means for retaining the clampsplates concentric with the core-box, and means for clamping the severalplates together.

10. 1 11 an. apparatus for ,the purpose described, in combination with upper and lower clamp-plates, a circumferentially circular separator element,"composed of a pluralit-y of separable adjacently vabutting segmental sections, two of which areprovided with oppositely disposed approximately straight joint faces, an intermaitching segmental section having end faces adapted to slide between the joint faces ofsaid two sections, .and means whereby said intermatchiug section can be withdrawn inward within the circle in the plane of the separator element.

lVitness my hand this'16th day of December, 1918.

AXEL W. CARLSON.

Copies of this patent may be obtained for five cents each, byaddressing the Commissioner-o1 Patents,

' Washington, D. 'G. 

